Bowed expander roll



Patented Mar. 10, 1942 U H'EE STATES ATENT OFFICE BOWED EXPANDER ROLLApplication October 24, 1939, Serial No. 300,955

6 Claims.

This invention is an improvement in bowed expanders of the Mycock typefor cloth and other continuous web material, and in particular relatesto the bobbins which are mounted on a stationary curved shaft, to forman articulated curved roll usually rotated by drawing the web materialover it, but sometimes otherwise driven, the outward component of travelof the surfaces of the bobbins as they rotate in planes oblique to thetravel of the material being utilized to open and expand the sheet ofweb material in both directions away from its middl line.

The bobbins comprising each roll are either interlocked or clutchedtogether, or else fixed tightly in a rubber tube or cover, to ensuretheir turning in unison, so as to attain uniform spreading action acrossthe width of the material. The present invention is concerned with theuncovered type of expander, in which the metal bobbins come directlyinto contact with the material being stretched.

In my prior Patent No. 2,131,692, granted Sept. 27, 1938, I havedisclosed an improved construction of uncovered expander bobbin in whichthe adverse effect of leaving the clutch dogs, which cause the bobbinsto turn in unison, exposed to contact with the material bein stretchedis avoided. Briefly, this is accomplished by form ing the ends of thecloth-engaging surface of each bobbin of continuous and unbrokencircular shape, with the clutch dogs which engage and drive the adjacentbobbin, and also the recesses receiving the corresponding dogs of suchadjacent bobbin, located wholly below and shielded by the cloth-engagingsurface of one or other of the adjacent bobbins.

It has been found that under certain circumstances the selvage of thecloth being stretched will enter the space left between these circularends of the substantially cylindrical cloth-engaging surfaces of twoadjacent bobbins, since this space extends clear around the entirecircuit of the roll at right angles to the axis thereof at suchlocation. On account of the out-v wardly-diverging action of theexpander roll on the fabric, the selvage of the cloth is itselftraveling very nearly at right angles to the axis of the roll at suchlocation, and on entering this substantially annular space described theselvage can and sometimes does become folded over, resulting in theformation of a doubled edge which gives trouble in subsequent finishing.operations.

Also, because the warps of the traveling cloth run practically in linewith this space between adjacent bobbins, there is a tendency for suchspace to crease or mark light fabrics.

The object of the present invention is to remedy these minor faults inthe patented structure, so as to enable its full benefit to be realized,and to these ends it provides a novel construction embodying theprinciple of disposing the joint between two adjacent bobbins of a bowedexpander roll so that no portion of such joint or space runs at rightangles to the axis of the roll at such location, but instead runs alwaysat some other angle, so that the joint or gap will traverse back andforth across the warps and thus both avoid the entry and consequentfolding of the selvage within the space and also distribut any mark ortrack of the gap back and forth across the warps so that it will not bevisible or conspicuous to the eye. This improved result may be attainedby any desired shaping of the ends of the clothengaging surfaces; of theadjacent bobbin which will cause such ends to be other than circular,

that is,.other than a straight line when the development of such end isprojected onto a plane surface. Preferably, the ends will be made in theshape of sinuous or undulating curves, though they may equally well bemade in zigzag form. To keep the joint or spacebetween adjacent bobbinsas narrow as possible, the opposing ends of two adjacent bobbins will beof identical but complementary shape, while the interengaging clutchesbelow the cloth-engaging surfaces will be employed as in the patent toprevent actual contact between the ends of the cloth-engaging portionsof the bobbins. Also, to maintain this spaced relation of such ends ofadjacent bobbins during the course of unavoidable wear of the coengagingsurfaces of the driving clutches, slight departures are made from thesine curve employed in giving the ends an undulant shape, as by cuttingaway the material forming the ends of the cloth-engaging surfaces at thepoints where the slope of suchcurve is at its steepest.

Other objects of the invention, and the manner of their attainment, areas made plain hereinafter.

Illustrative embodiments showing the invention in three preferred formsare shown in the accompanying drawing, in which,

Fig. l is an elevation of a portion of a bowed expander roll, taken atthe left-hand side of the center of such roll, illustrating two adjacentbobbins of my'improved construction in working relation upon theircurved shaft.

Fig. 2 is a development on a plane surface of a modified form of therespective curves of the. op-

usual sharp annular ridges or teeth 5 of vsawtooth shape in profilhaving '"a'rake "in the proper outward direction from mid-width of theroll, for enhancing the grip on the cloth, and the usualself-lubricating bushings are fixed curve of simple harmonic motion,which has been found useful in certain instances in prolonging theuseful life of the bobbins. As wear develops between the drivingshoulders of the clutches 9 and their sockets II, it results in a slightrelative axial rotation between the two bobbins involved, tending tonarrow the gap until contact occurs between the ends of thecloth-engaging surfaces of adjacent bobbins at and adjacent the pointswhere the slopes of the respective curves are the steepest, i. e., atthe points where each curve would cross its horizontal axis when drawn.on a graph. To prevent such contact, with the resulting burring of theends of the cloth-engaging .surfaces which tends to mark 'or pull"threads in the fabric being stretched by these rolls, the space betweenadjacent rolls is widened slightly at these localities by departingwithin the ends of each bobbin to bearagainstthe shaft 4. namedhereinbefore, clutch-dogs 9 of partly'segmental shape-are formed on bothends :of each bobbin at locations well below the cloth-engagingj-surface thereof, with intervening recesses H to receive thecorresponding clutch-dogs of the adjacent bobbin. The interengagement ofthese dogs and recesses compels rotation of all the bobbins in unison,as usual, and the bottoming of the -clutch-dogs within such recessesmaintains the ends 'of the cloth-engaging surfaces of each two adjacentbobbins in spaced relation to each other.

In accordance with the invention, the ends I3 of the cloth-engagingsurfaces of each bobbin in :Figs. 1 andd are formed in the shape ofsinu- :ous curves, that illustrated in Fig. 1 comprising two completecycles of a sine curve, and that in Fig. 4. comprising a single cycle ofa sine curve. The curves on opposite ends of each bobbin are identicaland complementary, and preferably are identical in shape throughout theentire series of bobbins forming a roll. Thus, as the rol-l rotates,there will be clearance avoiding wearrbetween the opposing ends'of thecloth-engaging surfaces "of each 'two :adjacent bobbins as the entireseries 'of bobbins rotates in unison, .as in the patent, and yet theposition of the clearance gap will shift back and forth along the axisof the roll with respect to any given fixed point in space, such as atthe .place where the adjacent ends approach most nearly to- :gether atthe concave side of the roll. Thus the gap traverses back and forthacross the warps of the cloth being drawn around the roll, which warpstravel in approximate alignment with the ridges 5, and any mark left bythe ends of the bobbin on fine goods is rendered harder for the eye toperceive- Because the selvages of the fabric likewise travel inapproximate alignment with the ridges 5, while the gap between adjacentrolls traverses back and forth across these ridges, there is no .portionof the gap having any substantial ex- .tent in the direction of :extentof the selvages,

and therefore the selvage either is prevented- 'Fig. 2 shows amodification-of the sine curve or In accordance with the patent "at:such points.

rand shaped'as indicated in solidlines, the orig- 'inal sine curve beingportrayed throughout this interval .in dotted lines. This modificationallows a considerable .amount of wear of the clutches and consequentre'lative rotation of the bobbins to take place before contact betweenthe ends :of the cloth-engaging surfaces can occur.

The modified form shown in Fig. Bfhas been found useful in certaininstances, the true zigzag line l3 followed :in forming the salient'andreentrant angles at the ends of the cloth-en- .gagling surfaces beingeasier to produce under certain processes .of machining and in certainmaterials. -Its operation inpreventing the mark- :ing and doubling ofthe selvage of "the fabric is as in the form first described.

While I have illustrated and described certain forms in which theinvention maybe embodied, I am aware that many modifications may be madetherein by any person skilled in the art, 'wi'thoutdeparting fromthescope .of the invention as expressed inthe claims. "Therefore, I donot wish to be limited .to the particular forms shown, or to the detailsof construction thereof, but

What Ido claim is:

-1. Ina bowed cloth expander, in combination, a .curvedshaft, and aplurality of bobbins -rotatably mounted on the shaft, each having itsclot-hengaging.surface terminating in a sinuous curve and with theconvex portions of such curveon one bobbin occupying the concave por-"tions'ofthe sinuous curve on the adjacent bobbin, and means'w-hollybelow 'the'cloth engaging surfaces holding the sinucusly-cu-rvedportions of adjacent bobbins apart from each other.

2. In a bowed cloth expander, in combination, a :curved shaft, and aplurality of bobbins roitatab'ly :mounted on the shaft, each :having theterminal margins .of its surface which engages .the cloth which is to beexpanded formed with alternate salient and 'reen'trant' portions andwiththe salient portions :on :one bobbin occupying the reentrant portions onthe adjacent "bobbin,

and means apart from the thus formed portions causing adjacent bobbinsto rotate in unison.

3. In a bowed cloth expander, in combination, a curved shaft, and aplurality of bobbins rotatably mounted on the shaft, each having asurface which engages the cloth which is to be expanded formed withsinuous curves at its ends, and the bobbins having mutually interlockingprojections additional to the portions formed with sinuous curvescompelling adjacent bobbins to turn in unison.

4. In a bowed cloth expander, in combination, a curved shaft, aplurality of bobbins rotatably mounted on the shaft, each having theterminal edges of its cloth-engaging surface disposed at other than aright angle to its axis throughout substantially the entirecircumference of the bobbin, and means below and apart from suchterminal edges causing adjacent bobbins to rotate in unison.

5. In a bowed cloth expander, in combination, a curved shaft, and aplurality of bobbins rotatably mounted on the shaft, each having theterminal edges of its cloth-engaging surface disposed at other than aright angle to its axis throughout substantially the entirecircumference of the bobbin and the bobbins having mu tuallyinterlocking projections extending axially beyond the end of thecloth-engaging surface of the bobbin on which they are located,compelling adjacent bobbins to turn in unison, such projections beingcovered by the cloth-engaging surface of the adjacent bobbin where theyextend within the length of such latter bobbin.

6. In a bowed cloth expander of the uncovered type in which the bobbinscome directly into contact with the cloth being stretched, a series ofbowed expander bobbins each having the ends of its cloth-engagingsurface formed in the shape of a sine curve, modified at the pointswhere the slope of the curve would otherwise be the steepest by reducingsuch slope, the convex portions of the sine curve on one bobbinoccupying the concave portions of the sine curve on the adjacent bobbin,and means wholly below the portions thus curved causing adjacent bobbinsto rotate in unison.

CHARLES W. SHUTE.

